AT28C040-20LC

Memory IC Overview

The AT28C040-20LC is a 4-megabit (512K x 8) parallel EEPROM manufactured using CMOS technology. It features a 200 ns maximum access time and operates on a single 5V ± 10% supply. The device utilizes a 44-pad ceramic leadless chip carrier (LCC) package and supports asynchronous operation with three-state outputs. Key electrical parameters include an active current of 80 mA and a standby current of 3 mA.

Memory IC Feature Summary

• Supports automatic page write operations for up to 256 bytes simultaneously, utilizing internal address and data latches.
• Includes hardware and software data protection mechanisms to prevent inadvertent writes during power transitions or system noise.
• Features DATA Polling and Toggle Bit functions to indicate the end of a write cycle without requiring external timing delays.
• Provides an extra 256 bytes of dedicated EEPROM memory accessible via specific voltage levels for device identification.

Memory IC Applications

• Nonvolatile storage for configuration data in industrial control systems
• Data logging applications requiring high endurance and long-term retention
• Embedded systems needing fast random access memory replacement

Memory IC Procurement Notes

Verify that the component matches the specified 44-pin LCC package and commercial temperature range. Confirm the manufacturer origin, as Atmel products are now under Microchip Technology. Ensure compliance with export regulations if applicable, as some variants may require additional documentation for international shipping.

Memory IC Selection Notes

Select this part when a parallel interface is required for direct static RAM-like access. The 200 ns speed suits moderate-frequency bus architectures. Consider the 44-pin LCC form factor for surface-mount assembly where space efficiency is critical but thermal dissipation must be managed within the 440 mW limit.

Memory IC Part Context

This component belongs to the AT28C040 series of paged parallel EEPROMs. It shares architectural similarities with other devices in the family, such as the AT28C256, but offers higher density. The 'LC' suffix specifically denotes the 44-lead Leadless Chip Carrier package variant intended for commercial temperature operation.

Memory IC Replacement Considerations

AT28C040-20LI

Memory IC FAQ

How does the device indicate the completion of a write cycle?

The AT28C040-20LC uses DATA Polling, where reading the last written byte results in the complement of the written data on I/O7 until the cycle completes. Alternatively, the Toggle Bit feature causes I/O6 to toggle between logic states during programming.

What is the purpose of the additional 256 bytes of memory?

These extra bytes are reserved for device identification or tracking purposes. They are accessed by raising address pin A9 to 12V ± 0.5V and writing to specific address locations.